Drill grinder



May 31, 1949. UN O 2,471,443

DRILL GRINDER Filed 001;. 10, 1945 4 4 Sheets-Sheet 1 INVENTOR BU DEN MUAEU I I BY Q jg. @W

ATTORNEY May 31, 1949. G, MUNRQ 2,471,443

DRILL GRINDER [505 mm MUNHD ATTORNEY G. MUNRQ DRILL GRINDER 4 Sheets-Sheet I5 INVENTOR EUHDUN MUNEU ATTORNEY May 31, 1949.

Filed Oct. 10, 1945 I VII/Ill May 31, 1949. G, NRO 2,471,443

DRILL GRINDER Filed Oct. 10, 1945 4 Shets-Sheet 4 INVENTOR EUEDUN MUNEU ATTORNEY Patented May 31, 1949 UNITED STATES PATENT QFFICE DRILL GRINDER Gordon Munro, Bremerton, Wash. Application October 10, 1945, Serial No, 621,643

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 157) 12 Claims.

This invention relates to drill grinders and more particularly to drill grinders adapted to sharpen twist drills.

This application is a continuation-in-part of my ccpending application Serial No. 589,434, filed April 20, 1945, entitled Drill grinder.

In the aforesaid application I describe and claim an improved drill grinder having a rotatably mounted grinding Wheel and a drill holding means mounted to pivot universally on horizontal and vertically disposed axes. The drill holding means is arranged to rotate a drill secured therein and to present the point thereof against a face of the wheel to grind the point automatically and precisely to a predetermined configuration. However, manually actuated means only are provided for swinging the holding means about its universal pivot axes and for rotating the drill. Furthermore, the position of the axis of rotation of the wheel is fixed with respect to the location on the grinding face that is contacted by the point of the drill; consequently wear on the Wheel is confined to a relatively narrow path on the grinding face.

Objects of the present invention are to provide I a drill grinder having a rotatably mounted grinding wheel and a drill holding means mounted .to swing on universal pivot axes and adapted to rotate a drill secured therein in which power driven means are provided for swinging the holder about its axes and rotating the drill; to provide a drill grinder having a rotatably mounted grinding wheel and a drill holding means in which the grinding wheel may oscillate to vary the position of the axis ,of rotation thereof with respect to a drill point held .thereagainst and .thus to promote uniformity .of wear of the wheel and decrease heating; and to provide a .drill grinder of the character described wherein means are provided for selectively oscillating the grinding wheel and in which said wheel may be manually adjusted across its path of oscillation either when it is or is not actually oscillating.

Other objects of the invention are to provide a drill grinder of .the type referred to in which means are provided for circulating a liquidcoolant and spraying the coolant on the grinding face; to provide a drill grinder in which the drill point angle ground on a drill secured therein may be varied by angularly adjusting :the drill holding means; to provide a drill grinder in which the drill holding means may be adjusted longitudinally and movement thereof is automatically stopped when the holding means is at a predetermined distance from the grinding face of the grinding wheel.

It is a further object of the invention .to provide for carrying out the foregoing objects in a facile, economical, and ,eilicient manner.

In accomplishing these and other objects of .2 the present invention, I have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a top plan view of a drill grinder embodying the features of the present invention, certain parts being cut away tomore clearly illustrate the mechanism.

Fig. 2 is a vertical sectional ,view of the upper portion of the drill grinder taken substantially on the line 2-2 of Fig. l, with the drill holding means being rotated about 3 Vertical axis to a position in which its longitudinal axis is parallel to the front of the frame of the grinder.

Fig. 3 is a vertical sectional view of the lower portion of the drill grinder, the figure being a continuation of Fig. 2.

Fig. 4 is a vertical sectional view of a detail of mechanism employed in the drill grinder taken substantially on the line 4-4 of Fig. 2.

Fig. 5 is a horizontal sectional yiew of a detail taken substantially on the line {5+5 .of Fig. 3.

Fig. .6 is a vertical sectional view .of a detail taken substantially the line .6- fi of Fig. 3.

Fig. l is a vertical sectional yiew of a detail taken substantially on the line l l of Fig. 1.

Referring more 'indetail to the drawings:

The drill grinder of my invention is preferably supported in a frame .or cabinet v l that comprises a table base section 2, a housing base section 3, and an end base section .4 The table base section 2 is located at the rearward portion of the rinder, or to the left as viewed inFig s. ,1, 2 and :3, and provides a support for a drilliholding means, an actuating means therefor, certain other mechanisms as be described hereinafter. The housing base 3 is located at the mid-portion of the grinder and provides a support principally for a grinding wheel, a lpeanS for oscillating the grinding wheel, a grinding wheehdressing means, and a housing for the wheel. The end base 4 is located at the forward portion of the grinder, or to the right as viewed'in Figs. 1 Z'and 3, and provides asupport,principallyior a motor adapted to rotate the grinding wheel, coolant tanks, and

a coolant pump. For convenience in manufacture and assembly, the sections 2, ,3 and ii are preferably made as separate ,castings or fabricated shapes of metal ,or other suitable material,

and are secured togetherlat their junctures.

Supported n the tsp o n? ar as 2 for longitudinal adjust-me t thereon is table 5. The-top of the tablebase is open except for mortised ledges adjacent the side walls that support and guide the table 5. As .shown in Fig. 2, the latter has a pairof tenonportions fi vthatengage within the mortisesofthcbase 2 and a bearin 5 pends .fro the r tinad end of said table. The ab bas Z'basaa crosaba pex endins la erally betweenitsside walls, a-ndthe :bar carries an interiorly threaded bearing member 9 that is axially aligned with the bearing "5. A feed screw it is journalled in the bearing '5 and retained in a fixed longitudinal position therein and threadedly engaged in the bearing member 9. Rotation of the feed screw it moves the table 6 in a longitudinal path across the table base 2. For convenience in rotating the feed screw ID, a hand wheel I l is secured thereto.

The upper face of the table contains an arcuate groove [2 which is preferably of inverted T-shape in cross-section, Figs. 1 and 2. A roller base holder I3 is supported on the table 5 and has an arcuate spline I4 on its lower face that its within the arcuate groove l2. The roller base holder may be angularly adjusted on the table and is guided in such adjustment by engagement of the spline l4 within the slot 2. The center about which the arcuate groove and spline are constructed is coincidental with the vertical axis on which the drill holding means swings, hereinafter described. The holder 13 may be clamped in adjusted position on the table 5 by means of set screws or bolts, not shown, that engage within the bottom portion of the groove 12.

The table 5 has a forwardly extending portion IE on which is preferably secured a bearing block 96, Fig. 2. A yoke I1 is pivotally mounted on the bearing block it for movement about a vertically disposed axis. The pivotal mounting preferably comprises a shoulder bolt 18 threadedly in a tapped bore in the bottom of the yoke and journaled within a suitable bore in the bearing block l6. A plurality of ball or roller bearings iii are preferably interposed between the yoke and the block to facilitate pivotal movement of the yoke on the block.

The yoke l! is substantiall U-shaped, having a pair of upwardly extending arms 26 and 2! preferably formed integrally with its base, Fig. 1. The arms of the yoke have horizontally aligned bearing apertures adjacent their upper ends. Pivotally mounted on the arms of the yoke through the bearing apertures for movement on a horizontally disposed axis is a saddle 22. The horizontally disposed axis on which the saddle pivots on the yoke is located rearwardly of the vertically disposed axis on which the yoke pivots on the bearing block l6 for a purpose explained in the discussion of the operation of the invention. The saddle extends rearwardly from the pivotal axis on which it is mounted and it is seen that the combination of the two pivotal axes provides a universal pivotal mounting for the saddle on which the latter may swing.

The saddle 22 has an annular bearing portion 23 rearwardly of the horizontal axis on which the saddle is mounted. The bearing portion 2-3 provides a pivotal mounting for a chuck that is adapted to support the forward portion of a drill 24 to be sharpened or ground in the grinder. An annular bearing ring 25 is threadedly secured in the interior of the bearing portion 23 of the saddle to retain the chuck mechanism, Fig. 2.

As here shown, the chuck comprises an annular ring gear 26 rotatably mounted in the hearing portion 23 of the saddle rearwardly cf the bearing ring 25, an annular bearing collar 27 rotatably mounted within the bearing ring 25 and extending forwardly thereof, and a cone bearing 28 having a central opening and being positioned forwardly of the bearing collar, Fig. 2. The ring gear 26, the bearing collar 21 and the cone bearing 28 are fixedly secured together to function as a unit by a plurality of machine screws 2'9.

A chuck cone 30 is mounted on the conical forward face of the cone bearing 28 for rotatable adjustment thereon and has a central opening for passage of a drill therethrough and peripheral radially disposed gear teeth 3! on its rearward face. One or more bevel gears 32 are rotatably mounted in suitable bearingapertures in the side wall of the cone bearing 23 and have teeth that mesh with the teeth 3| of the chuck cone 3!). The bevel gears 32 may be rotated from outside the chuck by use of a suitable tool and it is seen that such rotation rotates the chuck cone relatively to the cone bearing 28.

The chuck cone 36 has a pair of substantially identical spiral grooves 33 and 3A in its outer face, each of which extends through 360 and is out of phase with the other. A pair of chuck jaws 35 and 36 are supported against the outer face of the chuck cone 36 and have guide studs 3'! and 36 that ride within the spiral grooves 33 and 3d respectively. A face plate 39 of frusto-conical configuration, having a central opening for passage of a drill therethrough, is secured to the cone bearing 28 and covers the chuck cone 36 and jaws 35 and 3E. Th inner face of the face plate has diametrically opposed radial guideways through which the jaws 35 and 36 may slide in radial directions. The jaws each have at their inner ends a finger adapted to fit within the flute of a drill and a beveled face adapted to grip the margin of a drill preferably formed on separate replaceable jaw teeth secured to the inner ends of the jaws. It is seen that rotation of the chuck cone 30 relative to the cone bearing 28 moves the jaws 35 and 36 outwardly or inwardly simultaneously to increase or decrease the distance between the gripping portions of the jaws to grip or release a drill.

The chuck mechanism shown herein is described more fully and claimed in my copending application, Serial No. 621,661, filed October 11, 1945, now abandoned, entitled Chuck mechanisms. It is to be understood, however, that this chuck mechanism is merely exemplary of a chuck mechanism that is suitable for use in the drill grinder and that the mechanism may assume other designs; for instance, the chuck mechanism could be designed as in the drill grinder shown and claimed in my copending application, Serial No. 589,434, hereinbeiore referred to.

A pair of rods or bars 48 and M are fixedly secured to the upper face of the rearward portion of the saddle 22, and a center block 42 is slidably supported thereon, Figs. 1 and 2. A clamp block 63 is provided and is adapted to clamp the center block 42 in adjusted position on the rods 50 and ll. The center block 42 and the clamp block 43 have axially aligned tapped bores having right and left hand screw threads respectively or vice verse. that are engaged by an adjusting stud lt l having corresponding threads, Fig. 2. Rotation of the adjusting stud clamps the blocks 42 and 53 on the guideways t0 and ll or releases the blocks.

Preferably a handle 35 is provided to facilitate rotation of the stud M. The handle 45 is secured to the stud to transmit rotation thereto in either direction as desired. In the normal operation of the device rotation of the stud G l through only a small arc is sufficient either to secure the blocks against the guideways or to release them and the handle 45 may move through an arc sufficient for this purpose without interference from the other elements of the structure.

The center block 42 has an upstanding boss 46,

preferably integral therewith, that has an aperture therethrough axially aligned with the center of the chuck mechanism, Figs. 1 and 2. A drill center i! is threadedly engaged or otherwise supported within the apertur in the boss 46, with suitable bushing means preferably being provided for the engagement, as shown in Fig. 2. Preferably a hand wheel 48 is secured to the drill center 4? to facilitate adjustment thereof. The point of the drill center is adapted to abut axially against the shank of the drill 24 and thus to cooperate with the chuck in securing the drill in the drill holding means.

The drill center and the chuck mechanism cooperate to secure a drill within the drill holding means in such manner that the longitudinal axis of the drill is below the horizontal axis on which the saddle pivots on the yoke, for a purpose explained in the discussion of the operation of the invention.

It is seen that the chuck is adapted to secure a drill of any diameter up to the limit permitted by the size of the central opening through the face plate 39 and that the center block 42 may be adjusted longitudinally of the saddle 22 to accommodate any length of drill within the limit permitted by the length of the guideways 40 and 4|.

The saddle 22 has a rearward depending boss 59 and a forward depending boss 50 that contain axially aligned bearing apertures, Fig. 2. A shaft at is rotatably mounted in the bearing aperture in the forward boss 50 and has a shaft extension 52 coupled thereto by means of a coupling 53 for angular adjustment with respect thereto. The shaft extension 52 is rotatably supported in the bearing aperture in the rearward boss 49.

The forward boss 56 contains a vertically dis-. posed transverse slot 54 that communicates with the interior of the bearing portion 23 of the saddle. A pinion 55 is keyed or otherwise fixed to the shaft hi to rotate therewith within the slot d and the teeth thereof mesh with those of the ring gear 26. The diameter of the pinion 55 is half that of the ring gear 26 thus making a gear ratio of 2:1. When the shaft 5| is rotated by means hereinafter described, the gearing arrangement rotates the chuck mechanism and a, drill secured therein onc for each two revolutions of the shaft.

A pair of earns 56 and 51 are keyed or otherwise fixed to the shaft extension 52 to rotate therewith, Figs. 2 and 4. A roller base 58 is supported on the roller base holder [3 in a position fixed with respect thereto and carries a pair of rollers 59 and Eli. The cams 56 and 51 rest on the rollers 59 and 68 respectively and are cooperable therewith to swing the saddle about its universal axes of pivoting upon rotation of the shaft 5i and shaft extension 52 in a manner hereinafter explained in the discussion of the operation of the invention.

The shape of the outlines of the cams 56 and El may vary considerably and yet impart the desired motion to the saddle and a drill secured thereon; therefore the design of cams illustrated in Fig. 4 is to be considered only as an example of cams suitable for the purpose.

Cushioning springs 6! are preferably provided between the saddle 22 and the roller base holder l3, Fig. 2. The springs 6| are retained in position on telescoping supporting elements 62. Preferably one such cushioning spring is located oneach side of the shaft extension 52.

A drive pulley 63 is keyed or otherwise hated to the shaft 5! to rotate therewith, Fig. 2. A belt 64, preferably of the V-type, engages the pulley 63 to drive the pulley and shaft and thereby rotate the drill 24 and swing the drill holding means about the universal pivot axes. The belt 64 extends downwardly from the pulley 63 through suitable apertures in the roller base holder l3 and the table 5 into the lower portion of the interior of the table base 2, where it is engaged and driven by driving means about to be described.

A drive shaft 65 is rotatably mounted in suitable bearings in the frame l, Figs. 3 and 5. Preferably the bearings include a rear bearing bracket 68 secured to the front wall of the table base 2 and a forward bearing described hereinafter.

An idler pulley support 67 is mounted on the drive shaft 65 adjacent the bearing bracket 66. Preferably a bearing bushing 68 is provided and extends through the idler pulley support 61 and the bearing bracket 55 and rotatably receives the shaft 65. The bushing 68 may have an integral peripheral collar at one end and nuts 69 threadedly engaged therewith at the other end. The nuts 69 are tightened sufiiciently to prevent lateral play of the elements and yet permit the idler pulley support to pivot on the drive shaft 65 with respect to the bearing bracket.

A pulley i0 is keyed or otherwise fixed to the drive shaft 65 to rotate therewith. The idler pulley support 67 extends inwardly of the base 2 from the drive shaft 65 and provides a bearing for a stub shaft '7 I, Fig. 5. The latter is rotatable in the bearing provided therefor and has keyed or otherwise fixed thereto to rotate therewith a first idler pulley 72 and a second idler pulley 73. The first idler pulley is connected to the pulley 70 to rotate therewith by a belt it, preferably of the V-type. The second idler pulley receives the belt 64, hereinbefore referred to as connected to the pulley 63. It is thus seen that rotation of the drive shaft lid is transmitted to the shaft 5|, Fig. 2.

A tension spring 15, preferably of helical design, is connected at its upper end to the inner end portion of the idler pulley support 61 beneath the stub shaft H and at its lower end to thebot- .tom wall of the table base 2. The spring 75 pulls downwardly on the idler pulley support, and, acting through the belt (it, pulls down on the shaft 5|, thus assuring that the cams 56 and 5'! follow the rollers 59 and 56 at all times.

A drive motor M5 is mounted in the lower portion of the table base 2 and is operatively connected to the drive shaft 55 to rotate the latter through a set of reduction gears and pulleys, Fig; 3. A pulley. TI is connected directly to the motor to rotate therewith and drives a pulley [8 through a belt 19, preferably of the V-type. The pulley 73 is mounted on a shaft that is rotatably supported in suitable bearings in parallel transverse walls 86 and ti of the housing base 3'. The same shaft also has a gear 82 keyed thereto to rotate therewith and the teeth of the latter mesh with those of a gear 83 fixed to a second shaft also rotatably supported in suitable bearings in the transverse walls and 8!. The second shaft has fixed thereto another gear 84 that drives a gear 85 fixed to the drive shaft 65.

The housing base 3 has axially aligned bearings 86 and 81 in its upper portion, Fig. 2. A horizontally disposed spindle 88 is supportedv on the housing base 3 between the bearings 86 and 81. An elongated arm 89 is pivotally supported intermediate its ends on the spindle 88 for os'clflatory movement on a horizontally disposed axis.

The upper end portion of the arm 89 has a horizontally disposed bore 90, Fig. 2. A wheel spindle BI is rotatably supported in the bore 90, ball bearings 92 and 93 being preferably provided to facilitate the rotation thereof. The spindle has fixed thereto a wheel flange 94 at its rearward end and the latter carries a grinding wheel 95 of a standard design. The rearward face of the grinding wheel 95 functions as the grinding face and is positioned to be contacted by the point of a drill 24 secured in the drill holding means, Fig. 1.

The forward end of the wheel spindle QI has keyed or otherwise fixed thereto a pulley 96, Fig. 2. The end base 4 has a shelf or other support 9'! on which is mounted a motor 98. A pulley 99 is connected directly to the motor $8 to rotate therewith, the axis of rotation being aligned with the axis of oscillation of the arm 89 on the spindle 88. One or more belts I02], preferably of the V-type, connect the pulleys 96 and 99 to rotate the latter and the grinding wheel on rotation of the motor 98.

I have provided means operatively connecting the drive shaft 65 and the lower end portion of the arm 89 to oscillate the arm selectively on rotation of the drive shaft and to enable the arm to be adjusted manually across its path of oscillation independently of the oscillation.

As shown in Fig. 3, the wall 8I of the housing base 3 has a forwardly protruding boss II'II that has a central aperture therethrough. A worm wheel I92 is fixedly secured to the boss IOI as by the screws I03 and has a hollow central boss in registry with the central opening in the boss IIlI and fitted therewithin. A pivot base IE4 is provided and has a rearwardly extending boss I05 rotatably received within the central opening in the worm wheel I02. Nuts I06 are threadedly engaged on the boss IE5 to secure the latter within the openings. The pivot base IIM has a bore that passes centrally through the boss I05 and receives the drive shaft 65 and functions as a forward bearing therefor. Nuts III! are threadedly engaged upon the drive shaft to secure it in proper longitudinal position with respect to the pivot base.

The pivot base I04 has an aperture 168 therethrough, Figs. 3 and 6. A pivot block I69 is supported against the forward face of the pivot base I04 and has a stud portion I If! pivotally mounted in the aperture I98. The pivot block also contains a slot I II in which a slide block H2 is slidably supported. The forward end of the drive shaft 65 has an eccentric crank H3, preferably integral therewith, that is rotatably mounted in the slide block H2. Preferably a pair of arcuate guides H4 and H5 are secured to the forward face of the pivot base Ifl l to guide swinging movement of the pivot block on the pivot base. The arcuate guides are constructed about the stud I It! as a center. It is seen that rotation of the drive shaft 65 and of the eccentric crank IE3 thereon slides the slide block H2 within the slot III in the pivot block and oscillates the latter about the stud IIIl thereon as a center, such movement being guided by the guides H4 and I I5.

A swinging block HE is mounted for slidable adjustment in a suitable guideway on the forward face of the pivot block I82, Figs. 3 and 5, and carries a stud II? preferably integral therewith, Fig. 3. The lower portion of the arm 89 has a slot H8 in which is slidably mounted a slide block H9, preferably made in two sections as shown. The stud H1 is rotatably received in a suitable aperture in the slide block I I9.

The swinging block H6 may be adjusted b tween a position in which the stud II'I thereon is axially aligned with the stud I I0 and positions in which the stud I I1 is eccentric to the stud I It. It is seen that in the aligned position the stud I II merely rotates back and forth within the aperture in the slide block H9 and does not oscillate the arm 89, and that in the eccentric position the stud I I1, rotating in the aperture in the slide block I I9, imparts a sliding movement to the block I It within the slot H8 in the arm 89 and thereby oscillates the arm. The magnitude of the arc of oscillation may be varied by increasing or decreasing the eccentricity.

The means provided for adjusting the position of the swinging block H6 with respect to the pivot block I09 comprises a stub shaft I rotatably mounted at its mid-portion in a bearing aperture in the pivot base I64 and having fixed to its forward end a lever I2! and to its rearward end a worm wheel segment I22, Fig. 6. The inner end of the lever I2I is connected to the upper end of the swinging block H6 by a link I23 pivoted at its ends to the respective elements. A worm gear I24 is rotatably mounted in a suitable bearing I25 on the rearward face of the pivot base I64.

An operating shaft I26 is rotatably and slidably mounted in suitable bearings I21, I28, I29 and I39 on the rearward face of the pivot base I04, Fig. 6. Preferably the shaft I26 has secured thereto a collar I3I immediately beneath the uppermost bearing IZ-I. A compression spring I32, having just suificient strength to balance the weight of the shaft I26, is placed around the shaft between the bearing I28 and the collar I3 I. The spring I32 thus retains the shaft I25 in any desired vertically adjusted position. The shaft 12$ protrudes externally of the frame I through an elongated aperture I33 formed in a laterally extending portion I34 in a side wall of the housing base 3, Fig. 1. An operating handle I35 is preferably secured to the outer end of the shaft I26.

A clutch I36 is fixed to the shaft I26 below the worm gear I23, Fig. 6. The latter has a portion I31 adapted to be engaged with the clutch to transmit rotary movement of the clutch to the worm gear. When the operating shaft I25 is slidably moved to its upper position, Fig. 6, rotation thereof rotates the worm gear I24 to rotate the stub shaft I20 and lever I2I to raise or lower the' link I23 and the swinging block I I6 and thereby varies the eccentricity of the stud I I! with respect to the stud I ID.

A second worm gear I38 is rotatably mounted on the rearward face of the pivot base Iilll in a suitable bearing I39 and slidably and rotatably receives the operating shaft I26. The teeth of the worm gear I38 mesh with those of the worm wheel I02, which is fixedly secured to the wall 8i of the frame. The worm gear I38 has a portion I40 engageable with the clutch I36 when the latter is moved to its lowered position. Rotation of the worm gear I33 rotates the pivot base Ills and the entire assemblage mounted thereon with respect to the frame I. Such rotary movement is transmitted to the lower end of the arm 82 and thereby makes it possible for the arm to be manually adjusted across its path of oscillation independently of the oscillation imparted thereto by the drive shaft and irrespective of whether the arm is or is not actually oscillating.

Preferably the grinding wheel is encased within a housing MI within which it may oscillate, with an access opening being provided in the rearward face through which the drill 24 may pass, Fig. 1. The housing is slidably supported on the housing base 3 on suitable guide rods I42.

Preferably a means for dressing the grinding face of the grinding wheel 95 is provided and mounted on the housing base 3 and wheel housing I 4|. The dressing means preferably comprises a rotatable dresser shaft I 43, Fig. 1. A dresser arm I44 is fixed to the rearward end of the arm I49 to rotate therewith and carries a dressing stone I45 in position where the latter may be moved across the grinding face of the wheel 95 to dress the wheel. The opposite or forward end of the dresser shaft I43 carries a handle I45 for operating the dressing means. 7

The grinding face of the wheel 95 may be dressed by rotating the handle I45 and thus moving the dressing stone I45 across the face. The dressing process removes material from the face of the wheel and in effect moves the grinding face forwardly. As hereinbefore explained, the table may be adjusted forwardly by rotation of the hand wheel II of the feed screw It]. Forward adjustment of the table 5 moves the drill 24 forwardly to the same position relative to the grinding face that it occupied prior to the dressing operation and preferably means are provided for automatically stopping forward movement of the table when such position is reached.

The dresser shaft I43 is slidably and rotatably mounted within a hollow cylindrical sleeve I41. The rearward end of the latter is adapted to abut against the forward wall of the wheel housing MI and the forward end portion is screw threaded as indicated at I48. A hand wheel I49 is amxed to the forward end of the sleeve I41, and the threads I48 are engaged with those of a suitable tapped bearing I5I- affixed to the housing base 9. Rotation of the hand wheel I49 moves the sleeve I41 longitudinally of the frame and forward movement of said sleeve feeds the dresser shaft forwardly to enable the dresser stone to dress the grinding wheel.

As best shown in Fig. 7, the wheel housing I4I has a downwardly depending lug I5I. The table 5 has an upstanding lug I52 in substantially horizental alignment with the lug I5I. The lug I52 has an aperture I53 therethrough and a plunger I54 is slidably mounted in the aperture. A helical compression spring I 55 surrounds the plunger I54 and bears against collars on the plunger and lug in a manner illustrated in Fig. '1 to normally urge the plunger forwardly.

The rearward end of the plunger I54 is connected to a rearwardly extending rod I56, Fig. 1. A stop member I51 is pivoted to the top of the table 5 adjacent the rearward edge thereof and the rearward end of the rod I55 is pivotally connected to the stop member. The hand wheel II has a plurality of studs I58 projecting forwardly around its circumference that are engageable with the stop member I51 when the latter is moved rearwardly to prevent rotation of the wheel.

As best shown in Fig. 1, the dresser arm I44 has a portion that engages or abuts against the interior walls of the housing MI in such manner that movement of the dresser shaft I43 either forwardly or rearwardly is transmitted to said housing. During the dressing operation the dresser shaft moves forwardly a distance equivalent to the thickness of material removed from the grinding face and the housing MI is pushed forwardly the same distance.

The table 5 and the mechanism mounted thereon are moved forwardly by rotating the hand wheel I I. As the drill approaches the position relative to the grinding face that it occupied prior to the dressing operation, the forward end of the plunger I54 contacts the lug I 5| on the wheel housing I II, Fig. 7.

Further forward movement of the table 5 pushes the plunger rearwardly against the action of the spring I and the stop member I51 is thereby pivoted rearwardly into the path of one of the studs I58 on the hand wheel I I, preventing any more forward movement.

Preferably the drill grinder is liquid cooled. A pump I59, having a motor therein and being of a known design, is preferably mounted in the lower portion of the end base 4, Fig. 3. A plurality of settling tanks I are supported in the end base behind the pump I59, Fig. 1, and a suitable liquid coolant is placed within the tanks. The pump I59 draws the coolant from the forward tank and forces it through a conduit I6I, at least a portion of which is made of flexible material. From the conduit "if the coolant flows through a nozzle I62, secured to the wheel housing MI and having an outlet orifice in position to direct a stream of coolant over the face of the grinding wheel and the drill point.

The coolant returns to the tanks I69 through a drain aperture I53 in the top wall of the housing base 3, Fig. 1, the aperture being connected to the rearmost tank by a suitable conduit not shown. The coolant flows through the series of tanks I69 and any debris picked up thereby settles to the bottom of the tanks. The drain aperture I63 also provides a convenient passageway for the conduit IEI.

Operation A drill 24 to be sharpened is secured within the drill holding means. The chuck jaws 35 and 35 are moved into clamping engagement with the drill just rearwardly of the point thereof by rotating one of the bevel gears 32 with a suitable tool. The forward end of the drill center 41 is moved into abutting relation with the end of the drill shank. r

The roller base holder I3 is adjusted angularly on the table 5 to provide the desired drill point angle and clamped in place. The table 5 is moved forwardly to the extent permitted by engagement of the stop member I51 with one of the studs I 58 on the hand wheel II. The point of the drill is thereby brought into position to contact the grinding face of the grinding wheel 95. In such position the chisel edge of the point extends forwardly of the horizontal axis of pivoting of the saddle 22 on the yoke I1.

The motor 98 is energized to rotate the grinding wheel 95. The motor 16 is energized to rotate the drill and to swing the drill holding means about the universal axes of pivoting.

In the usual operation, when the grinder is viewed from the rear or from the left in Figs. 1 and 2, the grinding wheel rotates in a counterclockwise direction, the drill rotates in a clockwise direction, and the shaft 5|, shaft extension 52, and earns 56 and 51 rotate in a counterclockwise direction. However, all of the directions of rotation could be reversed and similar results obtained.

I shall consider one revolution of the drill during the grinding operation as constituting a grinding cycle. The shaft 5|, shaft extension 52, and cams 56 and 51 revolve twice during each grinding cycle, since the ratio of the diameter of 11 the gear 55 to the diameter of the gear 26 is one to two. The first part of the drill point to contact the grinding face is the cutting edge at the left as viewed from the rear. I shall consider the instant of such contact as the start of a grinding cycle.

At the start of a cycle the cutting edge as it contacts the grinding face is substantially horizontal and the shaft and shaft extension 52 are substantially in vertical alignment with the center axis of the roller base holder I3 and sloping slightly to the rearward. The cams 56 and 51 are at substantially their lowest positions on the rollers 59 and 6B.

As the cycle progresses, the cutting edge leaves the grinding wheel and the area of the rib behind the cutting edge progressively engages the grinding wheel. At the same time the cams 56 and 51 acting on the rollers 59 and 60 raise the rear end of the saddle 22 about its horizontal axis of pivoting on the yoke I1 and swing the yoke about its vertical axis of pivoting on the table 5 in a clockwise direction as viewed from above. Since the chisel edge of the drill point is forward of and. below the horizontal axis, raising of the rearward portion of the saddle lowers the chisel edge. The swinging on the vertical axis moves the rib engaged with the wheel closer to the wheel. The movement of the rib toward the wheel permits additional material to be ground from the rib behind the cutting edge to provide the necessary relief angle.

As the cycle progresses, the movement about the vertical axis decreases in order not to provide an excessive relief angle at the heel of the rib.

When the heel of the rib and the chisel point leave the wheel, the cams acting on the rollers lower the rearward portion of the saddle about the horizontal axis of pivoting and swing the yoke about the vertical axis of pivoting in a counter-clockwise direction as viewed from above. When the shaft 5| has completed one revolution, the drill has returned to the position it occupied at the start of the cycle except that the next rib is brought to a position to contact the grinding wheel. The counter-clockwise swinging of the yoke carries the point of the drill away from the wheel to allow the next cutting edge to come into grinding position without being damaged by premature contact with the grinding wheel.

The half grinding cycle just described is then repeated on the next rib.

When it is desired to increase or decrease the relief angle ground on the drill point, the shaft extension 52 is adjusted angularly with respect to the shaft 5| through the coupling 53. This adjustment advances or retards the instant at which the cutting edge of the drill engages the grinding wheel with respect to the instant at which the cams are at their lowest position. If the instant at which the cutting edge of the drill engages the wheel is advanced, a greater relief angle is provided.

After the grinding operation has been started, it is normally desirable to start the arm 89 to oscillating. Such oscillation of the arm oscillates the grinding wheel in the plane of its rotation to thereby spread wear on the wheel over a larger area.

The operating shaft I26 is shifted to its upper position thereby moving the clutch I36 into engagement with the worm gear I24. Oscillation is then started by rotating the handle I35 in a clockwise direction thereby rotating the worm wheel segment I22 in a counter-clockwise direction. Such rotation of the worm wheel segment I22 lowers the swinging block I I6 and thereby moves the stud II! to a position eccentric to the stud IIB. When the grinding has been partially completed, it becomes desirable to stop the oscillation during the finishing. Oscillation is stopped by reversing the operation just described and thereby moving the stud I I1 back into alignment with the stud I I0.

After oscillation has been stopped, it may be desirable to adjust the grinding wheel across its path of oscillation so that a particular portion thereof is engaged by the drill. To effect such adjustment the operating shaft I26 is moved to its lower position, thereby moving the clutch I36 into engagement with the worm gear I38, and the handle I35 is rotated in either direction as desired. Such rotation moves the pivot base IM about the axis of the drive shaft as a center to swing the arm 89 about the axis of the spindle 83 and thereby move the grinding wheel across its path of oscillation.

It has been hereinbefore pointed out that the axis of rotation of the pulley 99 is aligned with the axis of oscillation of the arm 89. This feature enables the oscillation to take place Without increasing the tension on the belts IGIJ or stretching the belts in any way.

Despite the oscillation of the grinding wheel, it is sometimes necessary to dress the wheel and this way be accomplished by operation of the dressing mechanism in a manner hereinbefore explained.

While I have shown but one embodiment of my invention, it is apparent that the device is susceptible to modification without departing from the spirit of the invention. I do not wish, therefore, to be limited by the disclosure set forth, but only by the scope of the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

1. In a drill grinder, a frame, an arm mounted on said frame for substantially planar oscillatory movement, a grinding wheel rotatably mounted on said arm and having a grinding face in a plane substantially parallel to the plane of oscillation of said arm, a lower base supported on said frame for longitudinal adjustment with respect to said grinding wheel, an upper base supported on said lower base for angular adjustment with respect thereto, a yoke mounted on said lower base for pivotal movement on a vertically disposed axis, drill holding means mounted on said yoke f-or pivotal movement on a horizontally disposed axis and adapted to secure a drill for rotation about its axis in position for the point thereof to contact said grinding wheel, a shaft rotatably mounted in said drill holding means, means for transmitting rotary movement of said shaft to a drill secured in said drill holding means, cam means secured to said shaft and rotatable therewith, means on said upper base with which said cam means is cooperable to swin said yoke about its vertically disposed axis of pivoting and said drill holding means about its horizontally disposed axis of pivoting upon rotation of said shaft, a, drive shaft rotatably mount ed on said frame, means for transmitting rotary movement of said drive shaft to said first named shaft, and means operatively connecting said drive shaft to said arm to impart oscillatory 13 movement to said arm upon rotation of the drive shaft.

2. In a drill grinder, a frame, a grinding wheel rotatably suporte'd on said frame, a lower basesupported on said frame for longitudinal adjustment with respect to said grinding wheel, an upper base supported on said lower base for angular adjustment with respect thereto, a yoke mounted on said lower base for pivotal movement on a vertically disposed axis, drill holding means mounted on said yoke for pivotal movement on a horizontally disposed axis and adapted to secure a drill for rotation about its axis in position for the point thereof to contact said grinding wheel, a shaft rotatably mounted in said drill holding means, means for transmitting rotary movement of said shaft to a drill secured in said drill holding means, cam means secured to said shaft and rotatable therewith, and means on said upper base with which said cam means is c-ooperable' to swing said yoke about its vertically disposed axis of pivoting and said drill holding means about its horizontally disposed axis of pivoting upon rotation of said shaft.

3. In a drill grinder, a frame, an arm mounted on said frame for substantially planar oscillatory movement, a grinding wheel rotatably mounted on said arm and having a grinding face in a plane substantially parallel to the plane of oscillation of said arm, drill holding means supported on said frame on universal pivot axes and adapted to rotatably secure a drill in position for the point thereof :to contact the grinding face of said grinding wheel, a drive shaft rotatably mounted in said frame, means operatively connected with said drive shaft for rotating a drill secured in said drill holding means and for swinging said drill holding means about its universal pivot axes upon rotation of the drive shaft, means opera'tively' connecting said drive shaft to said arm for oscillating said arm upon rotation of the drive shaft and thereby varying the position of said grinding wheel with respect to a drill secured in said drill holding means, means supported on said frame for dressing the grinding face of said grinding wheel, said drill holding means being adjustable forwardly and rearwardly on said frame to enable the point of a drill secured therein to be moved toward or away from said grinding wheel in accordance with the longitudinal position of the grinding face of said wheel, and means including an abutment movable with and prelocated in response to dressing motion of said dressing means into said grinding face of said grinding wheel stopping forward movement of said drill holding means at a predetermined position with respect to the grinding face of said grinding wheel.

4. In a drill grinder, a frame a grinding wheel rotatably supported on said frame and having a grinding face, drill holding means adapted to secure a drill for rotation about its axis in posi tion for the point thereof to contact the grinding face of said grinding Wheel, means supporting said drill holding means on said frame for universal pivotal movement about a pair of axes each normal respectively to each of a pair of mutually perpendicular planes, means supported on said frame for dressing the grinding face of said grinding wheel, said drill holding means being adjustable forwardly and rearwardly on said frame to enable the point of a drill secured therein to be moved toward or away from said grinding wheel in accordance with the longitudinal position of the grinding face of said wheel,

and means including an abutment movable with and prelocated in response to dressing motion of said dressing means into said grinding face of said grinding wheel stopping forward movement of said drill holding means at a predeter mined position with respect to the grinding face of said grinding wheel.

5. In a drill grinder, a frame, a grinding wheel fixed against axial motion relative to said frame, a table mounted on said frame for reciprocation in a direction normal to the plane of rotation of said grinding wheel, a chuck adapted to hold a drill to be ground by said grinding wheel and having means for gripping the drill so as always to orient the drill about its longitudinal axis with its flutes in the same position relative to the chuck jaws, means mounting said chuck on said table for movement relative to said table through a predetermined cycle of motion, manually operable means for moving said table relative to said frame, dresser means movable relative to said frame in the direction of the axis of said grinding wheel to dress said wheel, an abutment preset in response to axial motion of said dresser means, and stop means carried by said table and havin a first portion engageable with said abutment and a second portion movable in response to motion of said first portion for stopping the operation of said manually operable means, whereby said drill is always positioned in the same correct location relative to the grinding face of said grinding wheel regardless of the removal of material from said grinding wheel by dressing.

6. In a drill grinder, a frame, a grinding wheel mounted so as to be generally fixed against motion in the direction of its axis of rota-tion relative to said frame, dresser means for dressing said grinding wheel whereby the position of the grinding face is changed relative to a reference plane fixed in said frame, a chuck for holding a drill to be ground by said grinding wheel, mechanism for advancing said chuck relative to said grinding wheel, an abutment movable with the dresser means and prelocated in response to dressing movement of said dresser means in the direction of the axis of said grinding wheel, and means operable by engagement with said abutment to stop operation of said mechanism whereby said chuck is always located at the correct distance from said grinding wheel regardless of the displacement of the grinding surface by dressing.

'1. In a grinder of the character described, a frame, a grinding wheel carried by the frame, chuck means movably mounted on said frame for holding work to be ground against said grinding wheel, mechanism for moving said chuck means bodily relative to said frame toward said grinding wheel, dresser means for dressing said grinding wheel, an abutment movable with said dresser means and prelocated in response todressing motion of said dresser means into the grinding surface of said grinding wheel, and stop means cooperating with said abutment to stop said mechanism in order to limit movement of said chuck means toward said grinding wheel whereby said chuck means may always attain the same final position relative to the grinding surface of said grinding wheel regardless of the removal of material from the wheel by dressing.

8. In a drill grinder, a frame, a grinding wheel, drill holding means carried by said frame and adapted to secure a drill in position to contact said grinding Wheel to be ground thereby, means for oscillating said grinding wheel relative to said frame and said drill about an axis other than its axis of rotation while in contact with said drill whereby wear on said grinding wheel is distributed, means for varying the amplitude of oscillation of said grinding wheel to as little as zero while said grinding wheel remains in grinding contact with said drill whereby said drill may be rough ground and finish ground in rapid sequence and means for varying :the location relative to said drill of the midpoint of the oscillation of said grinding wheel to accommodate drills of difierent size held in said drill holding means.

9. In a drill grinder, a frame, an arm mounted intermediate its ends on said frame for substantially planar oscillatory movement, a grinding wheel rot-atably mounted on said arm adjacent an end portion thereof and having a grinding face in a plane substantially parallel to the plane of oscillation of said arm, the opposite end portion of said arm having a slot therein, drill hold- H ing means adapted to secure a drill in position for the point thereof to contact said grinding wheel, a drive shaft rotatably mounted on said frame, a worm wheel secured to said frame and having an axial bore, a pivot base having a boss rotatably fitted in the bore in said worm wheel and having an axial bore through the boss receiving the drive shaft, a plurality of axially aligned bearings secured to said pivot base, an operating shaft slidably and pivotally mounted in certain of said bearings and protruding externally from said frame, a pair of Worm gears rotatably mounted in certain of said bearings and having axial bores slidably and rotatably receiving said operating shaft, one or said worm gears being engaged with said worm wheel, a worm wheel segment rotatably mounted on said pivot base, the other of said worm gears being engaged with said worm wheel segment, said operating shaft having a clutch thereon selectively engageable with either or said worm gears, a block pivotally mounted on said pivot base for oscillatory movement and having a slot therein, said drive shaft having an eccentric crank engaged in the slot in said block to oscillate said block upon rotation of the drive shaft, a slide mounted on said block and having a stud engaged in the slot in said arm, and means operatively connecting said slide with said worm wheel segment whereby r0- tation of said worm wheel segment moves said stud between a position in which said stud is aligned with the pivotal mounting of the block on the pivot base and a position in which said stud is eccentric thereto for selectively imparting oscillatory movement to said arm upon rotation of said drive shaft.

10. In a drill rinder, a frame, an arm mounted intermediate its ends on said frame for substantially planar oscillatory movement, a grinding wheel rotatably mounted on said arm adjacent an end portion thereof and having a grinding face in a 'plane substantially parallel to the plane of oscillation of said arm, the opposite end portion of said arm having a slot therein, drill holding means adapted to secure a drill in position for the point thereof to contact said grinding wheel, a drive shaft rotatably mounted on said frame, a pivot base supported on said frame, a block pivotally mounted on said pivot base for oscillatory movement and having a slot therein, said drive shaft having an eccentri crank engaged in the slot in said block to oscillate said block upon rotation of the drive shaft, and means mounted on said block and engaged in the slot in said arm and being adjustable between a position in alignment with the pivotal mounting of the block on the pivot base and a position eccentric thereto for selectively imparting oscillatory movement to said arm upon rotation of said drive shaft and thereby varying the position of said grinding wheel with respect to a drill secured in said drill holding means.

11. In a drill grinder, a frame,-a grinding Wheel, drill holding means carried by said frame adapted to hold a drill in position to be ground by said grinding wheel, an arm pivotally mounted on said frame and rotatably carrying said grinding Wheel with its pivotal axis non-coincident with the axis of rotation of said grinding wheel, means for oscillating said arm to oscillate said grinding wheel including mechanism for varying the position relative to said drill of the mid-point of the oscillation of said grinding wheel comprising a pivot block, means mounting said pivot block for pivotal motion relative to said frame about an axis whose location relative to the pivotal axis of said arm determines the location of th midpoint of the oscillation of said arm and means operable during oscillation of said arm for varying the position of said mounting means to displace its axis relative to th pivotal axis of said arm whereby the position of the midpoint of the oscillation of said grinding wheel may be varied while the grinding Wheel is oscillating and grinding said drill.

12. In a grinding device of the character described, a frame, a grinding wheel, means carried by said frame to secure a workpiece in position to be ground by said grinding wheel, means for oscillating said grinding wheel across said workpiece during the grinding operation, means for varying the position relative to said Workpiece of the midpoint of the oscillation of said grinding wheel, and means remaining stationary independently of said oscillation of said grinding wheel and operable during the grinding operation and oscillation of said grinding wheel to actuate said position varying means.

GORDON MUNRO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 571,336 Budlong Nov. 17, 1896 777,247 Dahl Dec. 13, 1904 966,732 Brinkmann Aug. 9, 1910 1,016,891 Mill et al. Feb. 6, 1912 1,032,758 Lumsden July 16, 1912 1,546,453 Oliver July 21, 1925 1,710,647 Probert et al. Apr, 23, 1929 1,857,549 Jerczek May 10, 1932 2,098,267 Weishampel Nov. 9, 1937 2,252,303 Oliver Aug. 12, 1941 2,328,549 Ei-ch et a1. Sept. 7, 1943 2,363,482 Clarke Nov. 29, 1944 FOREIGN PATENTS Number Country Date 782,883 France Mar. 25, 1935 

